libs/hwui/tests/common/scenes/ListOfFadedTextAnimation.cpp

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "TestSceneBase.h"
#include "tests/common/TestListViewSceneBase.h"
#include "hwui/Paint.h"
#include <SkGradientShader.h>

class ListOfFadedTextAnimation;

static TestScene::Registrar _ListOfFadedTextAnimation(TestScene::Info{
        "fadingedges",
        "A mock ListView of scrolling text with faded edge. Doesn't re-bind/re-record views"
        "as they are recycled, so won't upload much content (either glyphs, or bitmaps).",
        TestScene::simpleCreateScene<ListOfFadedTextAnimation>});

class ListOfFadedTextAnimation : public TestListViewSceneBase {
    void createListItem(RenderProperties& props, Canvas& canvas, int id, int itemWidth,
                        int itemHeight) override {
        canvas.drawColor(Color::White, SkBlendMode::kSrcOver);
        int length = dp(100);
        canvas.saveLayer(0, 0, length, itemHeight, nullptr, SaveFlags::HasAlphaLayer);
        Paint textPaint;
        textPaint.getSkFont().setSize(dp(20));
        textPaint.setAntiAlias(true);
        TestUtils::drawUtf8ToCanvas(&canvas, "not that long long text", textPaint, dp(10), dp(30));

        SkPoint pts[2];
        pts[0].set(0, 0);
        pts[1].set(0, 1);

        SkColor colors[2] = {Color::Black, Color::Transparent};
        sk_sp<SkShader> s(
                SkGradientShader::MakeLinear(pts, colors, NULL, 2, SkShader::kClamp_TileMode));

        SkMatrix matrix;
        matrix.setScale(1, length);
        matrix.postRotate(-90);
        SkPaint fadingPaint;
        fadingPaint.setShader(s->makeWithLocalMatrix(matrix));
        fadingPaint.setBlendMode(SkBlendMode::kDstOut);
        canvas.drawRect(0, 0, length, itemHeight, fadingPaint);
        canvas.restore();
    }
};